1. Field of the Invention
The present invention relates to an apparatus for mounting a screen in a projection television, and more particularly, to the apparatus for mounting or separating the screen on or off the front surface of the projection television without using screws. The present application is based on Korean Patent Application No. 2001-81349, which is incorporated herein by reference.
2. Description of the Related Art
Generally, as shown in FIG. 1, a projection television comprises an optical system 30 disposed in the cabinet 20 in the lower case for generating an image by selectively penetrating a laser beam generated in a light source through a liquid crystal display (LCD) element and for enlarging and penetrating the image through a projection lens; a reflex mirror 40 disposed in the back of the upper part of the case 10 to tilt in a predetermined degree to reflect the image enlarged in the optical system 30 in the front surface; and a screen 50 disposed on the front surface of the upper case 10 to be exposed to the outside for penetrating or forming the image reflected by the reflex mirror 40.
Among these structural parts of the projection television, the screen 50 is fastened to the case 10 by a screen fastening device 1, as shown in FIG. 2.
The screen fastening device 1 comprises a front cabinet 61 forming a front window of the case 10 and a fastening bracket 70 for fastening the screen 50 to the front cabinet 60 using a number of screws 76.
The front cabinet 60 comprises a rectangular shape inner frame 61 supporting and holding the back of the screen 50 by the fastening bracket 70 and an outer frame 65 supporting and holding the front of the screen 50 by being combined with the inner frame 61.
As shown in FIGS. 3 and 4, the inner frame 61 comprises a screen receiving portion 63 for receiving and supporting the screen 50, and a fastening portion 64 having a number of screw bosses formed at predetermined intervals for fastening the fastening bracket 70 with screws 76 and also having four fastening bosses 66 at each corner of the front cabinet 60 for fastening the front cabinet 60 to the fastening portion (not shown) of the case 10. The outer frame 65 has a number of hooks 67, 67′ being hooked at the groove 69 through holes 68, 68′ formed on the inner frame 61 for hooking and fastening the inner frame 61.
Each fastening bracket 70 has a supporting portion 74 for supporting the screen 30, a fastening portion 73 having a number of screw holes through which the screws 76 pass to be inserted in the screw bosses 62 for fastening the fastening bracket 70 to the inner frame 61, and a connection portion 75 for connecting the supporting portion 74 with the fastening portion 73. The number of fastening brackets 70 which are r-shaped bars is four.
The conventional screen fastening device 1 described as above is assembled as below:
First of all, the outer frame 65 is disposed to the inner frame 61 as the hooks 67, 67′ pass through the through holes 68, 68′ of the inner frame 61 and hooked at the groove 69 and the screen 50 is disposed on the inner frame 61 for the front surface to contact with the screen receiving portion 63 of the inner frame 61 of the front cabinet 60.
The fastening bracket 70 is then placed on the back of the screen 50 and on the fastening portion 64 of the inner frame 61 for the supporting portion 74 to press the back of the screen 50 and for the screw holes to correspond to the screw bosses 62 of the inner frame 61.
The screws 76 are then put in the screw bosses 62 through the screw holes 72 of the fastening portion 74 for fastening the screen 50 to the inner frame 61 and the assembling can be completed when the inner frame 61 is fastened to the fastening part of the case 10 by the fastening bosses 66 and screws.
In case the screen is to be disassembled for repair or replacement, a cover (not shown) comprising the back of the projection television case 10 is separated first, and then the screen 50 is assembled by reversing the assembling process of the screen fastening device 1 described above.
However, the conventional screen fastening device 1 assembled and disassembled as above description has a problem of losing work efficiency and productivity as a large number of screws, for example 16 to 20 screws 76, are used for fastening the screen 50 to the inner frame 61.
Furthermore, in case the screen 50 is disassembled for repair or replacement, disassembling is complicated and takes a long time as the cover comprising the back of the projection television case 10 should be separated before the screws are fastened in the screw bosses 65 of the inner frame 61.